I went to Ivalo in 2013 for 2 weeks, on BA and Finnair. It was cloudy for first 7 days and then only saw aurora bow for another 7 days, no action. Discarded it for future trips. Driving around was a bit hazardous, almost every bend between Ivalo and Inari was icy and slippery an driving in winter conditions is standard for me. You also have to be careful of reindeer going on the road. Had much better luck with Aurora on my two visits to Kiruna, Sweden (no one world flights) and Tromso. Tromso is probably the best place in Europe. Also there's water so you can get nice photos of aurora reflection. One of my trips to Tromso was on the same date as Karfa so I have similar photos. The difference is, I was there for 2 weeks and Karfa was extremely lucky to get great show during short trip. It was beatiful night.

How about Alaska? You can do TP run to Seattle and continue on Alaska Airlines to Fairbanks. In my opinion it's the best place for northern lights and I'm going there for a third time in January. Some photos from 2016: https://goo.gl/photos/3UASN561VqRbcCvC9